Identification of long and very long chain fatty acids, plasmalogen-C16:0 and phytanic acid as new lipid biomarkers in Tunisian coronary artery disease patients.

Long and very long chain fatty acids (LCFAs and VLCFAs) may play an active role in coronary artery diseases (CAD) etiology. Our aim was to evaluate the associations between LCPUFAs (C20:4n-6; C20:5n-3 and C22:6n-3) and VLCSFAs (C22:0, C24:0; and C26:0), as well as markers of peroxisomal integrity evaluated by phytanic acid and plasmalogen-C16:0 (PL-C16:0) in addition to the markers of lipid peroxidation (malondialdehyde [MDA] and conjugated dienes [CD]) and inflammation (high sensitivity C-reactive protein [hs-CRP]) with vascular severity evaluated by Gensini score in order to determine their possible effects on CAD in Tunisian population. Lipidomic strategy based on GC/MS-SIM was used to quantify LCPUFAs, VLCSFAs, and PL-C16:0 in red blood cells of CAD patients, non-CAD patients, and controls. We observed a significant increase in phytanic acid, PL-C16:0 and VLCFAs, particularly C26:0, in CAD group compared to controls. Further our findings showed positive correlations of C26:0 with MDA and with vascular severity score (Gensini score). In addition, a significant negative correlation was shown between hs-CRP and C22:6 n-3 (r=-0.297; p=0.002) and a significant positive association was observed between hs-CRP and C20:4 n-6 levels (r=0.196; p=0.039). Our results show changes in LCPUFAs and VLCSFAs concentrations in RBC among study groups, and suggest alterations in fatty acids metabolism regulated by elongase and desaturase enzymes. The positive correlations of C20:4n-6 and the negative correlations of C22:6n-3, simultaneously with Gensini score and hs-CRP, suggest a link of both inflammation and vascular severity complication of CAD with LCPUFAs and VLCSFAs. Induction of lipid oxidation, can be one of the outcomes of LCFAs and VLCFAs accumulation in vascular tissues and, thus, playing an important role in the pathogenesis of atherosclerosis. Quantification of LCPUFAs and VLCSFAs, phytanic acid and PL-C16:0 simultaneously, would be of great value for the screening of peroxisomal disorders in vascular tissue of CAD patients.